If you are looking for a fun adventurous historical fiction for MG readers, The Detective's Assistant by Kat Hannifin is a great choice.
Synopsis (from Goodreads):
Eleven-year-old Nell Warne arrives on her aunt's doorstep lugging a heavy sack of sorrows. If her Aunt Kate rejects her, it's the miserable Home for the Friendless.
Luckily, canny Nell makes herself indispensable to Aunt Kate...and not just by helping out with household chores. For Aunt Kate is the first-ever female detective employed by the legendary Pinkerton Detective Agency. And Nell has a knack for the kind of close listening and bold action that made Pinkerton detectives famous in Civil War-era America. With huge, nation-changing events simmering in the background, Nell uses skills new and old to uncover truths about her past and solve mysteries in the present.
Nell is such a fun character and she has a strong unique voice. Smart and witty, she is more than a match and the best partner for her Aunt Kate, a Pinkerton detective. Kate is an excellent character in her own right, blazing a path for herself in a world that has not always been kind. Both Nell and Kate have suffered a lot of heartache. They are both prickly and wary of each other. Watching their relationship unfold over the course of the story was fun, endearing, and touching.
The story is rich in historical details, but is not encumbered by its historical significance. Important events occur and are discussed of but their purpose is in serving the lives of the characters rather than the characters serving the events. This is an important distinction for me in historical fiction, and one I find doesn't occur as often as it should.
My one complaint about the book is that it takes quite some time to get to the point. I feel like some of the set up could have been cut down to make the book shorter.
This is a great recommendation to give to kids who like adventure and humorous narrators.